Hydroponic Cultivation of the Medicinal Plant Scolymus hispanicus: Phytochemical Characterization and Biological Evaluation of Hydroponically Cultivated Scolymus hispanicus Root Extracts Using Biochemical and Bioelectric Approaches

Scolymus hispanicus L. (golden thistle) is an edible and medicinal Asteraceae species of Mediterranean origin. This study investigated the phytochemical composition and biological potential of root extracts obtained from hydroponically cultivated plants. Root powder was subjected to seven extraction conditions combining hot-water extraction, ultrasound-assisted extraction, and cold maceration using aqueous, ethanolic (75%), and mixed organic solvent systems. The extracts were first evaluated for total reducing capacity and antioxidant activity. Organic solvent-based extracts exhibited the highest total reducing capacity and strongest antioxidant activity, followed by ethanolic extracts, whereas aqueous extracts showed minimal activity. Cellular responses were assessed in immortalized human hepatocytes (IHHs) using the MTT assay and Real-Time Cell Analysis (RTCA) based on label-free cellular impedance measurements. Ethanolic extracts presented significant alterations in MTT-derived metabolic activity at lower concentrations (50 μg/mL) than aqueous extracts, and real-time monitoring indicated that the tested concentrations did not reduce the normalized Cell Index of IHH cells. LC–MS analysis of the selected ethanolic extract revealed sixteen characterized chromatographic features tentatively associated with caffeoylquinic acid-related, flavonoid-related, and other phenolic constituents. Furthermore, the extract produced measurable inhibition of Aliivibrio fischeri bioluminescence in the Microtox® assay under the experimental conditions tested. These findings demonstrate that root extracts from hydroponically cultivated S. hispanicus plants are sources of phenolic constituents with measurable antioxidant activity, supporting further investigation of their potential nutraceutical applications.